This invention relates to a process for executing several mutually complementary microscopic investigations of an object and to an apparatus for carrying out the process.
U.S. Pat. No. 4,011,748 discloses a process and an apparatus for acoustic and optical microscopy. The process makes possible both the simultaneous recording of an acoustic and an optical image of an object and the visual observation of it by means of an object detail imaged by an optical lens. The corresponding microscope comprises optical and acoustic systems of lenses, which focus light waves and sound waves in the same focal plane and convert the modulated light rays or acoustic waves reflected by or passing through the object into electric signals. The electric signals are then reproduced on the display screen of a cathode ray tube as a microscopic image of the object. The object is scanned and in the process moved through the focal plane in a grid pattern, which is synchronized with the cathode ray tube. It is also possible to leave the object stationary. In this case the entire microscope must be moved in the grid pattern with a drive synchronous with that of the cathode ray tube. By using a beam divider, the object image on the cathode ray tube may also be observed as in a conventional optical microscope. During reproduction of an image on the display screen of the cathode ray tube such a direct visual observation is not possible, because of the movement of the object or of the entire system in the grid pattern.
U.S. Pat. No. 3,790,281 discloses a combined system for simultaneous acoustical-optical investigation of a stationary object using a scanning laser beam and sonic waves. Because of the use of unfocused waves, no appreciable enlargement is possible with this apparatus. Furthermore, a partially reflecting and elastically deformable intermediate surface connected with the object is required to produce a specific wave pattern. The optical scanning of said wave pattern then produces an acoustical image, while no acoustical scanning takes place.
Japanese Utility Model application No. 56-22,172 describes a microscopic apparatus comprising an optical and an acoustical microscope, mounted fixedly on a base plate. Reversing means are provided between them, so that optical and acoustic microscopic observations may be effected successively. No simultaneous investigation by means of optical and acoustical objectives arranged on the same side of the object is possible with this apparatus because acoustical imaging requires a scanning motion performed by the object.
Finally, it is known (LEITZ-Mitt. Wiss. u. Techn. Vol. VIII, No. 3/4, pp. 61-67, Wetzlar, May 1982), to combine an acoustical scanning microscope with a reflected light microscope. This arrangement comprises a substructure with an object stage and an oscillator system with an acoustic objective that may be pivoted vertically into its operating position, and an incident light microscope mounted on a horizontally pivotable support. The latter may be brought into the working position over the object in place of the oscillator system with the acoustic objective. The acoustic and the optical microscopes are aligned with each other so that details of the object selected by the optical microscope may be found again subsequently in the acoustic microscopic image with scarcely any deviation. In the course of the necessary grid scanning of the object by means of the ultrasonic focus, the rapid movement in the linear direction of the grid is correlated with the objective of constant mass and the slow, stepwise motion perpendicular to the linear direction is correlated with the object stage with the object having a variable mass. No simultaneous optical examination of the latter is thus possible with this configuration.